Production of multimodal polythylene

a polyethylene and multi-modal technology, applied in the field of polyethylene preparation, can solve the problems of high molecular weight polyolefins that are difficult to process and can be costly to produ

Inactive Publication Date: 2002-02-12
FINA RES SA
View PDF9 Cites 114 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, high molecular weight polyolefins can ...

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Production of multimodal polythylene
  • Production of multimodal polythylene
  • Production of multimodal polythylene

Examples

Experimental program
Comparison scheme
Effect test

example 2

This Example used the metallocene ethylene bis (4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride of Example 1 in two reactors in series to produce a bimodal LLDPE polyethylene resin. The catalyst comprised 4 wt % on the support.

The catalyst was employed in a copolymerisation process to produce a polyethylene copolymer. In a first reactor of two serially connected reactors, the ethylene comprised 4 wt % and the hexene comprised 3.6 wt %, each in the off gas. The polymerisation temperature was 70.degree. C. and the residence time was 70 minutes. Hydrogen was added to the reactor in an amount of 0.2 Nl / h.

This first polyethylene product was used to constitute a first LLDPE fraction of an LLDPE bimodal resin which comprised a chemical blend of two separate polyethylenes. The second polyethylene produced in the second of the serially connected reactors using the same catalyst as for the first reactor comprised an LLDPE polyethylene.

In the polymerisation process to produce the second pol...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Percent by massaaaaaaaaaa
Densityaaaaaaaaaa
Densityaaaaaaaaaa
Login to view more

Abstract

A process for the preparation of polyethylene resins having a multimodal molecular weight distribution which comprises:(i) contacting ethylene monomer and a comonomer comprising an alpha-olefin having from 3 to 10 carbon atoms with a first catalyst system in a first reactor under first polymerisation conditions to produce a first polyethylene having a first molecular weight, an HLMI of not more than 0.5 g/10 min and a first density of not more than 0.925 g/ml and the first catalyst system comprising (a) a metallocene catalyst comprising a bis tetrahydroindenyl compound of the general formula (IndH4)2R''MQ2 in which each Ind is the same or different and is indenyl or substituted indenyl, R'' is a bridge which comprises a C1-C20 alkylene radical, a dialkyl germanium or silicon or siloxane, or an alkyl phosphine or amine radical, which bridge is substituted or unsubstituted, M is a Group IVB transition metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and (b) a cocatalyst which activates the catalyst component;(ii) providing a second polyethylene having a second lower molecular weight and second higher density than the first polyethylene, the second polyethylene having been produced using a catalyst other than the bis tetrahydroindenyl compound; and(iii) mixing together the first and second polyethylenes to form a polyethylene resin having a multimodal molecular weight distribution.

Description

BACKGROUND TO THE INVENTIONThe present invention relates to a process for the preparation of polyethylenes, having a multimodal molecular weight distribution, more particularly a bimodal or trimodal molecular weight distribution and exhibiting outstanding mechanical properties for blow-molding, film and pipe applications.DESCRIPTION OF THE PRIOR ARTPolyolefins such as polyethylenes which have high molecular weight generally have improved mechanical properties over their lower molecular weight counterparts. However, high molecular weight polyolefins can be difficult to process and can be costly to produce. Polyolefins having a bimodal molecular weight distribution are desirable because they can combine the advantageous mechanical properties of high molecular weight fraction with the improved processing properties of the low molecular weight fraction.For many HDPE applications, polyethylene with enhanced toughness, strength and environmental stress cracking resistance (ESCR) is import...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C08F110/02C08F210/00C08L23/00C08F110/00C08L23/06C08L23/08C08F210/16C08F4/00C08F4/659C08F4/64C08F4/642C08F10/02C08F4/6592C08L23/04
CPCC08F110/02C08F210/16C08L23/06C08L23/0815C08F4/65925C08F4/65927C08F2/001C08F4/24C08F4/65916C08L2314/06C08L2205/025C08L2308/00C08L2314/02C08L2314/04C08L2205/02C08L2666/04C08F210/14C08F2500/01C08F2500/02C08F2500/13C08F2500/07C08F2500/12C08F2500/05C08F2500/08
Inventor DEBRAS, GUYRAZAVI, ABBASMICHEL, JACQUES
Owner FINA RES SA
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap